Ink-jet recording apparatus and cap for eject port

ABSTRACT

The objective of the present invention is to provide an ink-jet recording apparatus which has a stable and widely applicable eject recovery means regardless of ink properties and recording head types for a compact and highly dense recording head equipped with a plurality of nozzles and nozzle rows. The ink-jet recording apparatus arranged as follows meets the above-mentioned requirements. A cap for capping a plurality of nozzle rows having a plurality of eject ports from which ink is ejected, communicating valves for communicating inner spaces of the cap to the atmosphere, a sucking means communicated to the cap for sucking ink from said nozzle rows, where; the cap is formed in one piece having a plurality of inner spaces corresponding to a plurality of eject ports, and a plurality of communicating valves are formed so as to communicate to the respective inner spaces and so as to control ejecting ink from nozzle rows by opening/closing operations by the communicating valves.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an ink-jet recording apparatusfor ejecting ink from a recording head, as a recording means, onto arecording medium, and also relates to a cap for capping eject portsduring ink sucking or nonprinting operations.

[0003] 2. Brief Description of the Related Art

[0004] Various kinds of recording methods, for example, wire-dotmethods, thermal methods, thermal transfer methods or ink-jet methodshave been proposed as mountable recording heads for recordingapparatuses to record on printing media, as media to be recorded, suchas paper, cloth, plastic sheets and OHP sheets etc. (Hereinafter alsosimply referred as “recording paper”).

[0005] Among these apparatuses, a printing apparatus employing theink-jet printing method (hereinafter also referred as the ink-jetprinting apparatus), where ink is ejected and deposited directly on therecording paper, is a non-impact printing method with low noise, capableof performing printings with high density and high quality. In generalthe ink-jet printing apparatus has a means for driving a carrier onwhich the print head is mounted, a feeding means for feeding therecording paper and a controlling means for controlling aforementionedmeans.

[0006] A piezo-electric element utilizing an electro-mechanical energyconversion module, a laser light irradiating method to generate thermalenergy for ejecting ink droplets or an electro-thermal energy conversionelement having a thermo-resistance element etc. have been known asenergy generating elements to generate energy for ejecting ink from inkeject ports of the print head.

[0007] Among the above-mentioned print heads, the print head of theink-jet printing method for ejecting ink as ink droplets by utilizingthermal energy is capable of printing with high resolution, since ejectports can be densely arranged. Above all, a print head utilizing theelectro-thermal energy conversion element as the energy generating canbe easily reduced in its size with densely packaged structure at lowcost by utilizing IC related technologies and micro-fabricatingtechnologies supported by advanced technologies and reliabilitiesattained in the recent semiconductor manufacturing field.

[0008] As mentioned above, the ink-jet printing method is the quiteexcellent printing method having a relatively simple arrangement, butstill there are problems to be solved.

[0009] When the ink-jet recording apparatus has not been used for a longperiod or when one particular eject port among a plurality of ejectports rarely ejects ink compared with other eject ports, ink ejection isdeteriorated in the ink-jet recording apparatus owing to ink thickeningby evaporation of water in ink around eject ports or an ink chambercommunicated to eject ports. Sometimes ejecting directions of ink aredeviated by deposited ink droplets, water droplets or foreign particleson the eject port surface of the head where eject ports are arranged.

[0010] In order to prevent the above-mentioned problems, theconventional ink-jet recording apparatuses have the following means asdevices for recovering ink ejection. For example, a pre-eject means forremoving thickened ink and the like by ejecting ink into an inkaccepting body before printing, an ink sucking means for sucking inkfrom eject ports and from common liquid chamber for removing depositedobjects, a sucking means for removing bubbles generated in ink duringexchanging ink tanks and a capping means for preventing waterevaporation from ejects ports are employed in conventional ink-jetapparatuses.

[0011] An ink-jet recording apparatus capable of color printing equippedwith the following arrangements has been developed: (a) a plurality ofeject port groups for magenta, cyan and yellow inks etc. except blackink arranged in the same recording head, (b) ink tanks and ink supplyingsystems independently arranged in the respective eject port groups, (c)a common capping means or an ink ejection recovery means for thesegroups. In this type of the recording apparatus, usually color imagesare formed by two or three colors except black color. When ejectingvolume of each color ink per dot are set the same volume as the blackink, dot diameters of the color ink recorded on the printing mediumextend too large.

[0012] As measures against enlarged color dot diameters, a head havingsmaller eject port diameters or nozzles with smaller cross sectionalareas for color inks are employed. Further in an ink ejection methodwhere liquid droplets are ejected by generated heat from thermal energygenerating elements etc., a head having smaller surfaced energygenerating elements or larger distance between the energy generatingelement and the eject ports are employed.

[0013] However the ink eject recovery means for the head or head unithaving a plurality of eject groups where different nozzle crosssectional areas or eject port sizes for respective eject port groups arearranged, has the following problem. Ejected ink volumes from respectiveeject port groups per one sucking recovery operation by the common capare different from each other owing to different flow coefficients inrespective eject port groups. In other words, larger ink volumes aresucked from eject port groups with larger flow coefficients and smallerink volumes are sucked from other eject port groups with smaller flowcoefficients.

[0014] When respective sucked ink volumes by the same sucking operationare different, sucking volumes should be set based on an eject portgroup with a minimum flow coefficient in order to remove bubblesgenerated during replacing the ink tank and thickened ink in inksupplying paths securely. Consequently, more ink volumes than requiredare sucked from other remaining eject port groups, as a result somevolumes of ink are wasted.

[0015] In the Japanese laid open patent No. 7-52406, a recording headand an ink eject recovery device etc. for solving the above-mentionedproblems are disclosed. According to the invention, since wasted inkvolume during the recovery operation is reduced by setting summed upvolumes of respective ink paths and a common liquid chamber according torespective flow coefficients of nozzles, the recovery for respectivenozzle groups is executed by the same cap for sucking. Which securelyreduces waste ink volumes.

[0016] However, in compliance with recent requirements such as morecompact sized recording apparatuses, printing images with higherresolution or higher printing rates etc., more compact sized recordingheads, smaller ink droplets from eject ports or higher ejecting velocityhave been required. Consequently, stored ink volumes in the commonliquid chambers are diversified according to the above-mentionedrequirements. Further since various types of inks such as ink with highcoloring and high light stability and ink with more stable fixing etc.have been increasing, inkjet recording apparatuses equipped withrecording heads to meet diversified flow coefficients and ink types aredeveloped. For example, an ink-jet recording apparatus primarily forrecording images with high quality and an ink-jet recording apparatusprimarily for higher printing rates etc. have been proposed.

[0017] An ink eject recovery device not only attaining stable ink ejectrecovering functions applicable to recent ink-jet recording apparatusesmentioned above, but also applicable to a recording head employable anytype of ink without wasting ink during recovery operation, is required.

SUMMARY OF THE INVENTION

[0018] The present invention is carried out in view of theabove-mentioned technical problems for providing an ink-jet recordingapparatus equipped with a stable and widely applicable ink ejectrecovery means for a compact sized recording head having a plurality ofdensely arranged nozzles and nozzle rows regardless of ink properties ortypes of recording heads.

[0019] The ink-jet recording apparatus according to the presentinvention is arranged as follows.

[0020] (1) An ink-jet recording apparatus comprising: a cap for cappinga plurality of eject ports for ejecting ink, a communicating valve forcommunicating the cap to an atmosphere, a sucking means communicated tothe cap for sucking ink from eject ports, where; the cap has a pluralityof inner spaces in an integrated form respectively corresponding toeject ports, and a plurality of communicating valves are provided so asto communicate to inner spaces respectively.

[0021] (2) The ink-jet recording apparatus according to (1) comprising:a recording head having a plurality of eject port rows for ejecting ink,a carriage for mounting the recording head to move reciprocatingly, acapping means for making the cap in contact to or separated from aneject port surface of the recording head, a switching means for openingor shutting communicating valves, where; the cap is formed in one piecehaving a plurality of inner spaces respectively corresponding to theeject port rows of the recording head.

[0022] (3) The ink-jet recording apparatus according to (2) where; apartition dividing the cap into a plurality of inner spaces is formed asone wall and a thickness of the partition is set equal to or less than athickness of other surrounding rib of the cap, and contact surfaces ofthe cap surrounding inner spaces to be in contact with the recordinghead are arranged on a same plane.

[0023] (4) The ink-jet recording apparatus according to (2) where thecapping means comprises; a cap holder to fix the cap, one or morecompression springs for applying pressure to the bottom plane of the capholder, a cap base for supporting the opposite ends of compressionsprings and for supporting the cap holder so that the cap holdergenerates a capping pressure against the eject surface of the recordinghead, and a cap lever for bringing the cap base closely to the recordinghead or for keeping the cap base away from the recording head.

[0024] (5) The ink-jet recording apparatus according to (4) where: onecompression spring of the capping means is arranged at the center ofgravity of a rib plane formed by a contacting plane contacting with theeject port surface of the recording head, or arranged below the ribplane along a perpendicular line to the rib plane passing through thecenter of gravity of the rib plane; or a plurality of compressionsprings of the capping means are arranged on or below the rib plane ofthe cap holder so as to surround a perpendicular line to the rib planepassing through the center of gravity of the rib plane.

[0025] (6) The ink-jet recording apparatus according to (1) where; thesucking means is formed as tube pumps for generating a negative pressurearound eject ports by pressing pressurizing rollers against tubesconnected to eject ports of the recording head so as to eject ink fromeject ports, and pressurizing rollers are moved in a direction forrelieving the applied pressure against tubes when pressurizing rollersare driven in a reverse direction to the pressure applying direction.

[0026] (7) The ink-jet recording apparatus according to (2), where; therecording head is equipped with electro-thermal energy conversionelements to generate thermal energy utilizing for ejecting ink.

[0027] (8) The ink-jet recording apparatus according to (7), where; inkis ejected from eject ports by utilizing film boiling in the ink causedby thermal energy generated from electro-thermal elements.

[0028] (9) A cap for use in an ink-jet recording apparatus for capping aplurality of eject ports for ejecting ink, where: the cap has aplurality of inner spaces in an integrated form respectivelycorresponding to eject ports.

[0029] (10) The cap according to (9), where: a partition dividing thecap into a plurality of inner spaces formed in one wall and a thicknessof the partition is set equal to or less than a thickness of othersurrounding rib of the cap; and contact surfaces of the cap surroundinginner spaces to be in contact with the recording head are arranged on asame plane.

BRIEF DESCRIPTION OF DRAWINGS

[0030]FIG. 1 is a perspective view illustrating the inner structure ofan ink-jet recording apparatus according to the present invention.

[0031]FIG. 2 is a perspective view illustrating an ink eject recoverydevice equipped in the ink-jet recording apparatus shown in FIG. 1.

[0032]FIG. 3 is an exploded perspective view illustrating the innerstructure of the ink eject recovery device shown in FIG. 2.

[0033]FIG. 4 is a perspective view illustrating a capping means equippedin the ink-jet recording apparatus shown in FIG. 1.

[0034]FIG. 5 is a plan view illustrating an arrangement of the cappingmeans shown in FIG. 4.

[0035]FIG. 6 is a partial perspective diagram illustrating a relationbetween the cap shown in FIG. 4 and an eject port area of a recordinghead linked to the cap.

[0036]FIG. 7 is a cross sectional side view illustrating the structureof the cap shown in FIG. 5.

[0037]FIG. 8 is a partial perspective diagram illustrating a geometricalrelation between the cap holder and the cap.

[0038]FIG. 9 is a perspective view illustrating a status where bothcommunicating valves to the atmosphere are closed (cap closed status)according to the present invention.

[0039]FIG. 10 is a perspective view illustrating a status where bothcommunicating valves to the atmosphere are open (dummy sucking status)according to the present invention.

[0040]FIG. 11 is a perspective view illustrating a status where thecommunicating valve to the atmosphere for color ink is open (black inkis in a sucking status) according to the present invention.

[0041]FIG. 12 is a perspective view illustrating a status where thecommunicating valve to the atmosphere for black ink is open (color inkis in a sucking status) according to the present invention.

[0042]FIG. 13A is a plan view illustrating a relation between onecompression spring and the cap holder and FIG. 13B is a plan viewillustrating a relation between several compression springs and the capholder according to the present invention.

[0043]FIG. 14 is a side view illustrating a detailed structure of asucking means equipped in the ink eject recovery device shown in FIG. 3.

[0044]FIG. 15 is a partial perspective diagram illustrating a shape of acap and an eject port area of a recording head linking to the cap.

[0045]FIG. 16 is a flow chart showing a series of eject recoveryprocedures according to the present invention.

[0046]FIG. 17 is a partial perspective view illustrating a structure ofink ejecting portion of the recording head equipped in the ink-jetrecording apparatus shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] Hereinafter referring to drawings, embodiments according to thepresent invention are explained. Throughout drawings the same signsrepresent the same members or portions. FIG. 1 is the perspective viewillustrating the inner structure of the ink-jet recording apparatusaccording to the present invention. FIG. 2 is the perspective viewillustrating the ink eject recovery device equipped in the ink-jetrecording apparatus shown in FIG. 1. FIG. 3 is the exploded perspectiveview illustrating the inner structure of the ink eject recovery deviceshown in FIG. 2.

[0048] A numeric character “1” is an ink-jet recording apparatusequipped with a carriage motor M1 as a driving source, a carriage 2 onwhich a recording head (recording means) 3 is mounted, a transmissionmechanism 4 which moves the carriage 2 reciprocatingly in directionsdepicted by an allow A by the carriage motor M1, a paper supplyingmechanism (a paper feeding mechanism) 5 which feeds (sends) a recordingpaper P, as a medium to be recorded, and an ink eject recovery device 10for recovering ejection from the recording head 3 by keeping the ejectport surface clean.

[0049] In the ink-jet recording apparatus 1, the recording paper P issent by the paper supplying mechanism 5 and required recording isexecuted on the recording paper P by the recording head 3. An inkcartridge 6 is demountably mounted on the carriage 2 on which recordinghead 3 is mounted.

[0050] Ink accommodated in the above-mentioned ink cartridge 6 issupplied to the recording head 3. In this case, the carriage 2 andrecording head 3 are properly contacted via respective contact surfacesso as to maintain a required electrical connection between them. Theabove-mentioned recording head 3 is a recording head for the ink-jetrecording apparatus where ink is selectively ejected from a plurality ofeject ports by applied energy to the recording head 3 in accordance withrecording signals.

[0051] The recording head 3 is a recording means for the ink-jetrecording apparatus to eject ink by utilizing thermal energy generatedfrom electro-thermal energy conversion elements arranged in therecording head. In other words the recording head 3 ejects ink fromeject ports for recording by utilizing pressure fluctuations caused bygrowing/shrinking bubbles from film boiling brought by applied thermalenergy from the above-mentioned electro-thermal energy conversionelements.

[0052] The electro-thermal energy conversion elements arrangedcorresponding to respective eject ports are elements for generatingthermal energy by applied voltages to the elements in accordance withrecording signals for ejecting ink from respective eject ports.

[0053]FIG. 17 is the partial perspective view illustrating the structureof ink ejecting portion (one eject port row) of the recording head(recording means) 3. As shown in FIG. 17, a plurality of eject ports 49are formed with a predetermined pitch on eject port surfaces 23 facingthe recording paper P with a predetermined spacing (for example, 0.3 to2.0 mm). Electro-thermal energy conversion elements (exothermicresistance etc.) 52 to generate energy for ejecting ink are respectivelyarranged along walls of respective liquid paths 51, via which respectiveeject ports 49 are communicated to a common liquid chamber 50.

[0054] The recording head 3 is guided and supported in a status wherethe eject ports 49 are arranged in a row crossing a main scanningdirection (in this embodiment the moving direction A of the carriage 2on which the recording head is mounted).

[0055] In the above-mentioned way, the recording head 3 is arranged toeject ink droplets from eject ports 49 by utilizing the generatedpressure by the film boiling in liquid paths 51 caused by appliedvoltages to respective electro-thermal energy conversion elements 52 inaccordance with image signals or ejection signals.

[0056] The carriage 2, shown in FIG. 1, is linked to a driving belt 7 ofthe driving mechanism 4, to which a driving force from the carriagemotor M1 is transmitted. The carriage 2 is arranged to slide along aguide shaft 13 in the direction of the arrow A, namely to movereciprocatingly in accordance with forward/backward rotations of thecarriage motor M1.

[0057] A numeric character “8” is a scale to indicate a position of thecarriage 2 along the direction of the arrow A. In this embodiment thescale 8 is formed out of transparent PET film on which black bars areprinted with a predetermined pitch. One end of the scale 8 is fixed to achassis 9 and the other end of the scale 8 is supported by a flat spring(not shown in drawings).

[0058] On the ink-jet recording apparatus 1 shown in FIG. 1, a platen(not shown) is arranged so as to face against the eject port surfacewhere eject ports (not shown) are formed. Along the full width of therecording paper P (as the recording medium) fed to the platen,recordings are executed by ejecting ink in accordance with recordingsignals to the recording head 3 together with reciprocating movements ofthe recording head 3 mounted on the carriage 2 driven by the drivingforce from the carriage motor M1.

[0059] A numeric character “14” is a feeding roller for feeding therecording paper driven by a feeding motor M2. A numeric character “15”is pinch rollers for pressing the recording paper against the feedingroller 14 by a spring (not shown). A numeric character “16” is pinchroller holders for rotatably supporting the pinch rollers 15.

[0060] A numeric character “17” is a feeding roller gear for driving thefeeding roller 14 via an intermediate gear 18 to which rotations of thefeeding motor M2 is transmitted.

[0061] A numeric character “19” is an ejecting roller gear fixed to anejecting roller 20 (not shown in FIG. 1) for ejecting the recorded paperwhere an image is formed by the recording head 3. The ejecting roller 20(see FIG. 2 and FIG. 3) is driven by revolutions of the feeding motor M2transmitted via intermediate roller 18 to the ejecting roller gear 19. Anumeric character “21” is a spurring roller for pressing the recordedpaper against the ejecting roller 20 via a spring (not shown). A numericcharacter “22” is a spurring roller holder for rotatably supporting thesupporting roller 21.

[0062] The ink eject recovery device 10 for recovering to a normalejection status in the recording head 3 is arranged at a desiredposition (for example a position facing against a home position of therecording head 3). But it should be arranged outside the reciprocatingmoving area for recording (outside recording area) of the carriage 2 onwhich the recording head 3 is mounted.

[0063] A capping means 11 for capping over the eject surface of therecording head 3 and a wiping means 12 for cleaning the eject portsurface of the recording head 3 are equipped in the ink eject recoverydevice 10. Together with the capping movement over the eject surface bythe capping means 11, ink is forcibly ejected by a sucking means (suchas sucking pump and the like, not shown in drawings) equipped in the inkeject recovery device. Thus the ink eject recovery procedure forremoving thickened ink and bubbles etc. in liquid paths is executed.

[0064] Capping over the eject port surface of the recording head 3during non-printing operations can prevent ink from drying as well ascan protect the recording head. The wiping means 12 is arranged in thevicinity of the capping means 11 so as to wipe up stuck ink on the ejectsurface of the recording head 3.

[0065] The capping means 11 and wiping means 12 can keep the recordinghead 3 in the normal status.

[0066]FIG. 4 is the exploded perspective view illustrating the internalarrangement of the capping means 11 shown in FIG. 1 and FIG. 2.Hereinafter the arrangement of the ink eject recovery device 10 whichincludes the ink eject recovery means, a characteristic feature of thepresent invention, is explained by referring FIGS. 2, 3 and 4. The inkeject recovery device 10 comprises a sucking means 48 (see FIG. 3), thecapping means 11 and the wiping means 12.

[0067]FIG. 14 is the side view illustrating a detailed arrangement ofthe sucking means 48. The sucking means 48 in FIG. 14 comprises asfollows. Two sucking tubes 32 are guided along an inner circular surfaceof a base cover 20 of the sucking means. Two pressurizing rollers 33having respective axes are arranged to each sucking tube. Thepressurizing rollers 33 are pressed against the sucking tubes 32 bysprings (not shown in drawings) for generating negative pressure insucking tubes 32. Pressurizing rollers 33 are placed in oval openings ofpressurizing roller holders 31 so that the pressurizing rollers 33 arein pressing positions against sucking tubes 32 during sucking operationsand in idle positions during non-sucking operations.

[0068] In this embodiment, since the base cover 20 has semicircularsurface, one of the two pressurizing rollers 33 always presses againstthe sucking tubes 32 while the other pressurizing roller 33 is in theidle position by arranging two pressurizing rollers 33 in the oppositeside of a circle formed by the base plate cover. Thus, continuoussucking operations are attained when pressurizing rollers 33 arerevolved continuously with keeping the negative pressure in the suckingtubes 32.

[0069] When the base cover has a full circular surface, even onepressurizing roller may attain the same result as mentioned above. Evenwhen the base cover has the semicircular surface, the continuous suckingoperations are realized by employing two or more pressurizing rollers.The pressurizing roller holders 31 are fitted to a pressurizing rollerholder guide 30 so as to revolve in a radial direction of the base cover20 for attaining a cyclic pressurizing/idle positioning of pressurizingrollers 33 against sucking tubes 32.

[0070] The pressurizing roller holder guide 30 has axes on its bothsides and rotatably fitted to the circular center formed by the innersurface of the base cover 20 where sucking tubes 32 are arranged viatheir axes. A driving power from a PG motor (recovery motor) M3 shown inFIG. 2 and FIG. 3 is transmitted to and revolves the pressurizing rollerholder guide 30 via PG gear 24 and a pump gear 27 arranged in thesucking means 48 so as to execute sucking recovery operations.

[0071] The revolving drive from the PG motor M3 is directly linked tothe sucking means 48 so as to revolve in a circular direction for thesucking operation (hereinafter referred as “forward revolution”) and torevolve in a reversed direction for moving the pressurizing rollers 33from a pressurizing status to a pressure free status against suckingtubes 32 (hereinafter referred as “backward revolution”). In thisembodiment, the sucking means 48 is driven by one driving source in therecovery device, but other different driving sources are also applicableto the sucking means 48.

[0072] As shown in FIG. 4, the capping means 11 comprises as follows: acap 35 directly connected to the eject surface of the recording head 3;cap absorbers 44 for absorbing ejected ink from eject port surface ofthe recording head 3 effectively; a cap holder 36 for supporting the capand for pressing the cap 35 against eject port surface of the recordinghead 3 via compression springs 43; a cap base 34 for supportingcompression springs 43 so as to apply a pressure against the cap holder36 and for supporting cap holder 36 so as to flexibly slideupward/downward; a cap lever 37 functioning as an arm to press or removethe cap 35 against or from the eject port surface of the recording head3; communicating tubes 45 to the atmosphere for communicating the capbase 34 and communicating holes 47 (shown in FIG. 9 to FIG. 12) to theatmosphere formed in the cap base 34 and communicating valves 46 a (forblack ink) and 46 b (for color inks) for opening or closingcommunicating holes 47 so as to make the cap 35 open or close.

[0073] In the capping means 11, the sucking tubes 32 of the suckingmeans 48 are linked to joints formed on the cap holder 36 so as to suckink from the recording head 3 by applying the negative pressure causedby the sucking movements of the sucking means 48 to the cap 35 as far asthe capping means is pressed against to ink eject port surface of therecording head 3.

[0074]FIG. 5 is the plan view of the cap 35 shown in FIG. 4. FIG. 6 isthe partial perspective view showing the contacting area between the cap35 in FIG. 4 and the eject port surface. As shown in FIG. 5 and FIG. 6,a plurality of nozzle rows, a black ink nozzle row 54 and color inknozzle rows 55, are arranged in the recording head 3. Consequently, thecap 35 is divided into two areas, one for a black ink cap area 57 andthe other for a color ink cap area 58. Two cap absorbers 44 fitted inthe cap by cap absorber pressing ribs 56 are arranged in respective capareas 57 and 58. Two communicating tubes to the atmosphere andcommunicating valves 46 a and 46 b to the atmosphere supported by thecap base 34 via axes with applied pressure from valve springs 53 arealso arranged in the capping means. Characters “X” in FIG. 5 designatecrossing points of black ink cap rib and color ink cap rib.

[0075] Openings 42 a (sucking side) for guiding the sucking tubes 32 tothe cap holder 36 and openings 42 b (atmosphere side) for guidingcommunicating tubes 45 to the cap holder 36 are formed on respective inkcap areas 57 and 58 so that each sucking tube and communicating tube isengaged to joints formed on the cap holder 36.

[0076] Upward/downward movements of the capping means 11 for pressing tothe recording head and open/close movements of valves 46 a and 46 b areexecuted by the driving force from the PG motor M3. The driving forcefrom the PG motor M3 is successively transmitted to a PG gear 25, to aPG gear 26 and to a one-way clutch gear 28 which is mated to a cum 38(see FIG. 3). The one way clutch gear 28 transmits the driving force tothe cum 38 when the PG motor M3 revolves in one direction and the oneway clutch gear 28 disconnects the driving force to the cum 38 when thePG motor M3 revolves in the reverse direction.

[0077] The above-mentioned cum 38 controls not only movements of theabove-mentioned capping operations but also drives the wiping means 12and controls upward/downward movements of a CR lock lever 29 (see FIG.2) for positioning the recording head 3 and the capping means during inkeject recovery operations of the recording head 3. A revolving positionof the cum 38 is determined by a cum position detecting sensor 40 and aflag for shielding the cum position detecting sensor equipped to the cum38 so as to control respective means.

[0078] The present invention relates to ink-jet recording apparatusequipped with the recording means having a plurality of eject port rowsfor ejecting ink, the carriage on which the recording means is mountedmoving reciprocatingly and the ink eject recovery means for recoveringor keeping the normal ink ejecting statues in eject ports. In addition,the present invention includes features that are explained hereinafter.Characteristic features of sucking recovery modes in the ink ejectrecovery device of the ink-jet recording apparatus and of the cappingmeans are explained by referring FIG. 7 to FIG. 16.

[0079]FIG. 16 is the flow chart showing the sucking operations for ejectrecovery in one of the embodiments. The sucking operations for ejectrecovery by the ink eject recovery device against the recording head 3are executed according to a sequence shown in FIG. 16. Hereinaftersucking recovery modes are explained in detail according to the sequencein FIG. 16. Sucking operations for eject recovery are carried outaccording to instructions from a CPU (not shown in drawings) based on aprogram stored in a ROM (not shown in drawings).

[0080] When a sucking instruction for eject recovery is issued, aposition of the cum 38, a member of the eject recovery device, isdetected by the cum position detecting sensor 40 and positions of thecapping means 11 and the wiping means 12 etc. are confirmed (step S101).When the recording head 3 is not at the sucking position for ejectrecovery, after confirming that the recording head 3, the capping means11 and wiping means 12, members of the eject recovery unit, are not in astatus where they do not interfere each other by the cum positiondetecting sensor 40, the recording head 3 is moved to the suckingposition for eject recovery by the transmission mechanism 4 shown inFIG. 1 (step S104). When the recording head 3 is in the position of theeject recovery operation, the recording head 3 is moved away from theposition (step S102) and the PG motor M3 is revolved in the reversedirection (R direction) (step S103) until the wiping operation isfinished. Then the recording head 3 is moved in a position of thesucking for eject recovery (step S104).

[0081] The capping means 11 is pressed against the eject port surface ofthe recording head 3 by revolving the cum 38 revolved by the PG motor M3so as to execute the sucking operation for eject recovery (step S105).In this step, since the revolving direction of the PG motor M3 is in thereverse direction (R direction in FIG. 14), the pressurizing rollers 33of the sucking means 48 are positioned away from sucking tubes 32 wherethe inside of the cap 35 communicates to the atmosphere so that inkremaining in sucking tubes 32 does not flow into the inside of the cap35 and physical damages against eject ports of the recording head 3 dueto the positive pressure are prevented. (The PG motor M3 is revolved inthe reverse direction until a PG sensor is activated.) After pressingthe cap 35 against the eject port surface of the recording head 3, thePG motor M3 in the sucking means 48 is revolved in the forward direction(L direction in FIG. 14) so as to press the pressurizing rollers 33arranged in the sucking means 48 against the sucking tubes 32 as apreparation for the sucking recover operation (step S106, an initialoperation before the sucking movement of the pressurizing rollers).

[0082] In this step since the capping means is pressed against the ejectport surface of the recording head 3, communicating valves 46 a and 46 bare kept in the open status (see FIG. 10) by revolving the cum 38 toavoid an excessive negative pressure inside the cap 35, when the suckingmeans 48 revolves in the reverse direction (R direction).

[0083] The above-mentioned operation is executed so as to reducefluctuations of sucked ink volume by making the pressurizing rollers 33start rotating in the L direction from the pressurized status againstthe sucking tubes 32 whenever sucking recovery operations are started.Since sucking operations for eject recovery are respectively set for theblack ink and color ink, a sucking mode is selected (step S107). Theselection of the sucking modes are executed by opening/closingoperations of communicating valves 46 a and 46 b which control thepressure inside the cap 35 while the cap 35 is pressed against therecording head 3 by controlling communicating valves 46 a and 46 b. Morespecifically, a negative pressure is generated inside of the cap 35 bythe sucking recovery means 48 with the aid of communicating valves 46 aand 46 b.

[0084] As shown in FIG. 9 to FIG. 12, the pressure inside the cap 35 iscontrolled by opening or closing communicating valves 46 a and 46 b. Inthe present invention, communicating valves 46 a and 46 b can controlthe respective pressures of inner spaces of the cap 35, which is formedas one-pieced body.

[0085]FIG. 9 is the perspective view illustrating closed status ofcommunicating valves 46 a and 46 b where the cap protects the eject portsurface of the recording head 3. FIG. 10 is the perspective viewillustrating a status where the communicating valves 46 a and 46 b areopen for keeping inside of the cap 35 in communicating status to theatmosphere and for ejecting ink inside the cap 35 before the suckingoperation for eject recovery (the above-mentioned initial operationbefore sucking operation by the pressurizing rollers). FIG. 11 is theperspective view illustrating a status where the black ink is sucked(the communicating valve 46 a for the black ink is closed) FIG. 12 isthe perspective view illustrating a status where color inks are sucked(the communicating valve 46 b for color ink is closed).

[0086] After selecting sucking modes, the driving force from the PGmotor M3 is transmitted to the sucking means 48 so as to suckpredetermined respective volumes of the black and color inks (revolutionnumbers of the sucking pump are set differently for the black ink andcolor inks) according to respective sucking instructions (step S108).Then as shown in FIG. 10 communicating valves 46 a and 46 b are openedby revolving the cum 38 for ejecting ink inside the cap 35.

[0087] After bringing communicating valves 46 a and 46 b into openstatuses, a dummy sucking operation for ejecting sucked ink inside thecap 35 is executed by driving the sucking means 48 in the L directionvia driving force from the PG motor M3 (steps S109, S110). Thus a usualsucking operation for eject recovery is finished. The sucking modes foreject recovery are executed by combining the single sucking mode of theblack ink, the single sucking mode of color ink and continuous suckingmode of black and color inks.

[0088] In order to carry out the above-mentioned sucking operation foreject recovery stably, the present invention takes the followingmeasures.

[0089]FIG. 7 is the cross sectional side view showing the cap structurein FIG. 5. FIG. 8 is the partially perspective plan view depicting thegeometrical relation between the cap holder 36 and the cap 35. The space57 for the black ink and the space 58 for the color ink in the cap 35 inthis embodiment are different from each other in their shapes as shownin FIG. 5 and FIG. 7. When the predetermined capping pressure is appliedto the capping means 11 after pressing against the eject port surface ofthe recording head 3, applying positions of compression springs 43 tothe cap holder 36 are set on a line formed by the plane of the capholder 36 and its perpendicular plane passing through the center ofgravity G of a plane of the cap rib 41, at the opposite sides inrelation to the line so that the predetermined pressure can be stablyapplied to the recording head 3 pressed against the cap rib 41.

[0090] A uniformly distributed pressure to even one-piecedasymmetrically formed cap, which tends to be unstable by the appliedpressure, is attained by applying the pressure to the center of gravityG of the cap rib plane 41. In order to form stable closed space betweenthe cap 35 and the eject port surface of the recording head, the planeof the cap rib 41 pressed against the eject port surface are preferablyarranged on the same plane (in other words heights Z shown in FIG. 7from the bottom to cap rib planes should be the same). Since points X,cap rib crossing points, are harder to deform than other cap ribportions, a width T1 of the center portion of the cap rib (width of theouter-periphery of the cap rib) dividing the black ink space 57 andcolor ink space 58 is set equal to or less than a width (a width of acap partition rib) T2 of the other surrounding cap rib portions, namely,T1≦T2.

[0091]FIG. 13A and FIG. 13B are plan views illustrating arrangements howpressures from compression springs 43 are applied to the cap holder 36.

[0092] As shown in FIG. 13A, one big compression spring 43 capable ofapplying a pressure over a wide area is arranged at the center ofgravity G of the rib plane or below the rib plane along a perpendicularline to the rib plane passing through the center of gravity G of the ribplane, to the rib plane so as to attain the same effect as theabove-mentioned embodiment (see FIG. 8).

[0093] The same effect is attained when several compression springs 43are arranged as shown in FIG. 13B. Several pairs of compression springs43 are arranged in the same way as in the case of FIG. 8, when springsare positioned on or below the plane of the cap holder 36 so as tosurround a perpendicular line to the plane of cap rib 41 passing throughthe center of gravity G of a plane of cap rib 41.

[0094]FIG. 15 is the perspective view of the other embodimentillustrating the vicinity of eject port surface of the recording head 3pressed against the cap 35 having a plurality of spaces. Even arecording head with high density having nozzle rows 59 for differentcolors as shown in FIG. 15 may attain the same effect as previouslydescribed embodiments, when three respective spaces with one cap havesucking means and communicating valves respectively.

[0095] The present invention may provide an ink-jet recording apparatusequipped with the stable and widely applicable to ink eject recoverymeans capable of capping over the compact recording head having aplurality of nozzles and nozzle rows regardless of ink properties andrecording head types.

[0096] In the above-mentioned embodiments, the serial type ink-jetrecording apparatus where the recording means moves relatively againstthe recording medium is explained as the example where the ejectrecovery means is employed. But the present invention is also applicableto a full or a partial line type recording means for a line type ink-jetrecording apparatus that attains the same effect.

[0097] The present invention may be applicable to a recording apparatushaving one recording means, a color recording apparatus having aplurality of recording means for different colors or a gradientrecording apparatus having a plurality of recording means for differentcontrasts of the same color and may be also applicable to anycombination of preceding recording apparatuses, which can attain thesame effects as the embodiments described above.

[0098] Further the present invention may be applicable to anyarrangement of the recording head and the ink tank such as thearrangement having an exchangeable cartridge where the recording headand the ink tank are formed in one piece, or the arrangement having inksupply tubes etc. connecting the individually formed recording head andthe ink tank, which can keeping the same effects as the embodimentsmentioned above.

[0099] The present invention may be applicable to a recording headhaving electromechanical energy conversion elements such aspiezo-electric elements etc. However, the present invention may be mosteffectively applied to the ink-jet recording apparatus having therecording means where ink is ejected by utilizing thermal energy amongvarious recording head types, since recordings with high density andwith fine pattern can be relatively easily attained in the thermalenergy type recording head.

[0100] As mentioned above, the present invention comprises the followingfundamental arrangements. In the ink-jet recording apparatus equippedwith the recording head having a plurality of nozzles and nozzle rowsejecting ink from eject ports thereon and the carriage on which therecording head is mounted, the cap for capping a plurality of nozzlesfor ejecting ink from eject port thereon, communicating valves forcommunicating the inner spaces of the cap to the atmosphere,opening/closing means for the communicating valves, the sucking meanscommunicated to the cap sucking ink from the eject ports for ink ejectrecovery are arranged. The cap is formed in one piece having a pluralityof the inner spaces corresponding to a plurality of the nozzle rows. Thecap is equipped with the capping means for connecting/disconnecting thecap to eject port surfaces of the recording means. The cap has aplurality of inner spaces to which valves are communicated,communicating valve opening/closing means for closing or communicatingthe inner spaces of the cap against the atmosphere and the sucking meansfor sucking ink from the recording head for ink eject recovery.

[0101] The above-mentioned cap has respective partitions formed as onewall dividing the cap into a plurality spaces where the thickness of thepartitions is set equal to or less than that of other surrounding ribsand planes pressing against the eject port surface of respective spacesare arranged on the same plane. The capping means comprises the capholder for fixing the cap, compression springs pressed against thebottom surface of the capping means, the cap base for supporting thecompression springs from the opposite direction and for supporting thecap holder so as to generate the capping pressure in the capping holderagainst eject port surface of the recording head and the cap lever forconnecting or disconnecting the cap base to the recording head.

[0102] The above-mentioned arrangement provides the ink-jet apparatusequipped with the stable and widely applicable to eject recovery meansregardless of ink properties and recording head types, where cappingoperations against the compact and highly densified recording headhaving a plurality of nozzles and nozzle rows are realized.

[0103] In the above explained arrangement, one compression spring of thecapping means, as pressing means, is arranged on the center of gravityof the rib plane contacting with eject port surfaces or below the ribsurface along the perpendicular line to the rib plane passing throughthe center of gravity of the rib plane. Or a plurality compressionsprings are arranged on or below the plane of the cap rib so as tosurround the line perpendicular to a plane of cap rib passing throughthe center of gravity G of the plane of cap rib. As a result even in theasymmetrically shaped cap capping pressure on the eject port surface ofthe recording head may be applied with good balance, which enable toprovide the ink-jet recording head having more stable eject recoverymeans.

[0104] Since the sucking means employs the tube pump where the negativepressure is generated at the eject ports by pressing the sucking tubesconnecting to eject ports of the recording means via the capping means,ink sucking volumes may be set variably according to desired volumesregardless of ink properties and recording head types by adjustingoperating duration of the pump, consequently, more widely applicableeject recovery device can be provided.

[0105] As mentioned above the present invention attains the followingeffect. The ink-jet recording head having the stable and widelyapplicable eject recovery means capable of capping against a pluralityof nozzles and nozzle rows and adjustable to respective eject recoveryconditions may be provided regardless of ink properties and recordinghead types.

What is claimed is:
 1. An ink-jet recording apparatus comprising: a capfor capping a plurality of eject ports for ejecting ink, a communicatingvalve for communicating said cap to an atmosphere, a sucking meanscommunicated to said cap for sucking ink from said eject ports, wherein;said cap has a plurality of inner spaces in an integrated formrespectively corresponding to said eject ports, and a plurality of saidcommunicating valves are provided so as to communicate to said innerspaces respectively.
 2. The ink-jet recording apparatus according toclaim 1 comprising: a recording head having a plurality of eject portrows for ejecting ink, a carriage for mounting said recording head tomove reciprocatingly, a capping means for making said cap in contact toor separated from an eject port surface of said recording head, aswitching means for opening or shutting said communicating valves,wherein; said cap is formed in one piece having a plurality of saidinner spaces respectively corresponding to said eject port rows of saidrecording head.
 3. The ink-jet recording apparatus according to claim 2wherein; a partition dividing said cap into a plurality of said innerspaces is formed in one wall and a thickness of said partition is setequal to or less than a thickness of other surrounding rib of said cap,and contact surfaces of said cap surrounding said inner spaces to be incontact with said recording head are arranged on a same plane.
 4. Theink-jet recording apparatus according to claim 2, wherein said cappingmeans comprises: a cap holder to fix said cap, one or more compressionsprings for applying pressure to a bottom plane of said cap holder, acap base for supporting the opposite ends of said compression springsand for supporting said cap holder so that said cap holder generates acapping pressure against the eject surface of said recording head, and acap lever for bringing said cap base closely to said recording head orfor keeping said cap base away from said recording head.
 5. The ink-jetrecording apparatus according to claim 4 wherein: said one compressionspring of said capping means is arranged at the center of gravity of arib plane formed by a contacting plane contacting with the eject portsurface of said recording head or below the rib plane along aperpendicular line to the rib plane passing through the center ofgravity of the rib plane; or said compression springs of said cappingmeans are arranged on or below the bottom plane of the cap holder so asto surround the perpendicular line to rib plane passing through thecenter of gravity of the rib plane.
 6. The ink-jet recording apparatusaccording to claim 1, wherein; said sucking means is formed as tubepumps for generating a negative pressure around said eject ports bypressing pressurizing rollers against tubes connected to eject ports ofsaid recording head so as to eject ink from said eject ports, and saidpressurizing rollers are moved in a direction for relieving the appliedpressure against tubes when said pressurizing rollers are driven in areverse direction of applying the pressure.
 7. The ink-jet recordingapparatus according to claim 2, wherein; said recording head is equippedwith electro-thermal energy conversion elements to generate thermalenergy utilizing for ejecting ink.
 8. The ink-jet recording apparatusaccording to claim 7, wherein; ink is ejected from eject ports byutilizing film boiling in the ink caused by thermal energy generatedfrom said electro-thermal elements.
 9. A cap for use in an ink-jetrecording apparatus for capping a plurality of eject ports for ejectingink, wherein: said cap has a plurality of inner spaces in an integratedform respectively corresponding to said eject ports.
 10. The capaccording to claim 9, wherein: a partition dividing said cap into aplurality of said inner spaces is formed in one wall and a thickness ofsaid partition is set equal to or less than a thickness of othersurrounding rib of said cap, and contact surfaces of said capsurrounding inner spaces to be in contact with said recording head arearranged on a same plane.